1. Field of the Invention
The subject of the present invention is a means and a device for the real time measurement of the motion of a mobile rigid structure under the influence of a fluid, such as an aircraft model in a wind tunnel, a drilling platform or a model of a seagoing vessel in a test basin. The following description will deal more particularly with the latter case of a structure floating in a test basin. It is particularly important to be able to determine the position in the water of a model vessel in the course of hydrodynamic testing in basins where swells of varying amplitude and frequency can be generated, in order to be able to predict the behavior of the vessel concerned under real sailing conditions.
2. Description of the Prior Art
Measurement of the position of a model in a testing basin is generally carried out with the help of a mechanical follower installed at the vessel's stern. This arrangement suffers from certain disadvantages since a mechanicl contact must always be arranged between the vessel whose performance is to be studied and the measuring system itself.